Shutter for photographic cameras



(No Model.)

R. D. CLEVELAND 8v G. A. HOFFMAN.

SHUTTER FUR PHOTOGRAPHIG CAMERAS.

Mtn/asses.

Patented May 7,1889.

N. Krans. mmm-mog uw. wmmmn. n. c.

'UNITED STATES RALPH D. CLEVELAND ANT) CHARLES A. HOFFMAN, OF MINNEAPOLIS PATENT OFFICE.

MINNES OTA.

SHUTTER FOR PHOTOGRAPHIC CAMERAS.

SPECIFICATION forming part of' Letters Patent No. 402,806, dated May 7, 1889.

Application filed May 23, 1888.

To @ZZ whom it may concer/t:

Be it known that we, RALPH D. CLEVE- LAND and CHARLES A. HOFFMAN, of Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Shutters for Photographic Cameras, of which the following is a specification.

Our invention relates to an improvement in a device for operating the shutters used for excluding the light from a photographic camera, and the object we have in view is to provide a shutter which can be used both for an instantaneous and protracted exposure without any change in the operating meehanisin.

Our invention consists, generally, in the construction and arrangement hereinafter described, and particularly pointed out in the claims.

In the drawings which form a part of this specification, Figure 1 is a front elevation of our improved shutter, showing the operatingbulb connected thereto. Fig. 2 is a side elevation of the same. Fig. 3 is a front elevation and partial section, on an enlarged scale, showing the operating-cylinder and shutter-blades in position for a protracted exposure. Fig. 1- is a front elevation showing the parts in position after having made an instantaneous exposure. Fig. 5 is a front elevation with. the outer plate removed to more clearly show the operation of the shutter-blades. Fig. 6 is a transverse section taken. on line t 0c of Fig. 4f. Figs. 7 and S are detail sections showing the operation of the cylinder.

1n the drawings, 2 represents the face-plate of the shutter, upon which the operatingcylinder 3 is located. t represents the back plate, of substantially similarI size to the plate 2, and this plate is preferably attached to the screw-cap 5,by which the device is secured to the camera. A ring, G, is preferably placed between the two plates 2 and 1t, which conforms to the outer circumference of the said plates and allows a space between them within the ring for the sluitter-blades 7 and 9. These blades are free to swing within the said space.

The blade 7 is supported by a pivot-pin, 12, and the blade 9 by a pin, 13. Each blade is provided with an armatnre,19, and when the Serial No. 274,771. (No model.)

blades are vertically in line, as shown in full lines in Fig. 5, the apertures 10 register with each other and with a corresponding opening in the plates 2 and i. A pin, 15, is preferably passed through the blades at a point between the pivots 12 and 1S, and by moving this pin in a straight line to the right or left will cause the blades to swing on their pivots in opposite directions and close the aperture 10.

The cylinder 3 is preferably open at one end, and is provided with the inlet-pipe 17 at the other. A hollow follower, 19, iits closely within the cylinder in which it slides. The outer end of the follower is provided with a head, 21, and the inner end is open to the interior of the cylinder. A piston, 22, is arranged within the follower 19 Yand is free to slide therein. As this piston is forced outward, it strikes the solid head of the follower 19 and forces it outward to the limit of its stroke.

A iiexible tube, 23, may be introduced over the inlet-pipe 17 and provided with a co1npression-bulb, 25, for the purpose of forcing air into the cylinder. A dog, 27, is preferably pivoted to the cylinder and provided with a lip, 29, arranged to fail in front of the follower-head and retain it in its retracted position. A beveled catch, 30, is preferably formed upon the head 21 in line with the dog 27, and is so arranged that the lip :29 will fall back of this catch where the follower is in its extreme outward throw and be retained in this position.

A linger, 32, having an inclined upper surface, is secured to the piston and slides through an opening in the head 2l. rllhe inclined surface of this vfinger bears against the lip 29 and raises it out of contact with the head.

The pin 15, which operates the shutterblades, is preferably connected to the head 2l.

A stop, 234, is preferably pivoted upon the plate 2, and may be brought in contact with the head to limit its forward motion, as shown in Figs. G and 7, when the apertures inthe slides and plate correspond. This is used where a protracted exposure is required.

A valve, 323, may be placed in the inlet-pipe for the purpose of holding the pressure of air in the cylinder and preventin the return of the piston.

A spring, 31, may be located upon the plate IOC i f i Y Y 2. rlhe upper end of this spriugis preferably attached to the follower by a suitable connecting-link, 35. The opposite end. is preferably attached to the plate by a pin, 3G, around which it is free to swing.

A tension-brace, 37, is pivoted upon the plate 2, with its outer end arranged to bear against the spring 3l. The point at which the brace 37 is pivoted is eccentric with the curve of the spring, so that as the said brace is moved about its pivot it will bear against the 'spring and increase its tension. Suitable pin-holes, 39, may be placed radially about the pivot of the brace 37, and a suitable pin or projection on the brace may be arranged to iit either of the holes and hold the brace in contact with the spring in any required position. lVhen the brace is in the position shown in Fig. 3, it is out of contact with the spring, and the said spring is free to swing about the pin 3G and exert no tension upon the follower. lVhen it is desired to use the device for an instantaneous exposure, the brace 37 is brought in contact with the spring and secured in one of the holes 39, and the tension of the spring is exerted to throw the follower forward and instantaneously open and close the aperture 10. Any other convenient device may be used to secure an adjustable tension upon this spring.

The operation of the device is as follows: When the device is in its normal position, the follower 19 is retracted, the head 21 resting against the end of the cylinder, and the pis ton 22 is also drawn back to its extreme limit. The lip 29 on the dog 27 will then engage the front of the head 21, and the pin 15 on the said head, in contact with the shutter-blades, will cause them to take the position denoted by dotted lines in Figs. 1 and 5, and the aperture 10 will be closed. Vhen it is desired to make an ordinary exposure, the stop 34 is placed in a horizontal position, as shown in Figs. 1, 3, and 7, thus bringing it in line with the travel of the follower. The bulb 25 is now compressed and the air forced into the cylinder 3. The compressed air in the cylinder acts against the piston 22, forcing it forward. The iinger 32, attached to the said piston, slides out through the slot in the head of the follower. The inclined upper surface of this finger strikes the lip 29 and raises it out of contact with the head 21. The piston 22 advances in the follower until the end of the said piston strikes the head 21, which, being now free from the retaining-dog 27, will be forced out by the advancing piston until it strikes the stop 34, as shown in Fig. 3. lVhen this position is reached, the pin 15, operating the two shutter-blades, will be in line with the pivots 12 and 13, and the said blades will stand in their middle position with the aperture 10 open, as denoted in full lines in Fig. 5 and in dotted lines in Fig. 3. This position of the parts may be maintained for any length of time by keeping the bulb compressed and the air-pressure in the cylinder. Then the pressure is released from bulb, the distension of the said bulb will suiliciently exhaust the air from the cylinder and draw the piston and follower back to their original positions. The retaining-dog 27 will again engage the head. The shutter-blades will be closed and locked.

It may be convenient in some instances to hold the shutter open without retaining the pressure upon the bulb. In order to do this the cock or valve 33 is provided, which controls the opening for admitting the air-pressure from the bulb to the cylinder. lVhen the air is compressed in the cylinder sufliciently to operate the piston and follower, as before I described, this valve may be turned to cut off the iiow. The ai r-pressure will then be retained in the cylinder and the shutter remain open for any length of time after the bulb has been released, and will so remain until the valve 33 is opened. i

For an instantaneous exposure we prefer t throw the shutter-blades from one extreme to the other, or from the position shown in dot ted lines in Figs. 1 and 3 to the position shown in Fig. et. The apertures in the blades will register for an instant in the passage by each other. To accomplish this result, the full stroke of the follower 19 is required, and the stop 34 is raised, so as not to be in contact with the head.

The piston and follower are operated as before described, except that the follower is thrown outward to the limit of its stroke, and when in this position the lip 29 falls behind the catch 30 and the shutters are locked in this position, thus avoiding the possibility of a double exposure. Vhen greater speed and certainty are necessary in the action, the brace 37 is brought in contact with the spring. This causes the tension of the spring to act upon the follower. In this instance the airpressure merely raises the catch and releases the follower, which is immediately drawn out by the pressure of the spring.

Vhat we claim as our invention is 1. In a photographic-camera shutter, the combination of the two shutters arranged one over the other and provided with openings adapted to register with each other, pivots arranged at unequal distances from said openings and supporting said shutters, and a pin engaging both of said shutters at a point between said pivots, whereby as the pin is moved in either direction the said shutters are moved upon their pivots in opposite directions, substantially as described.

2. In a photographic-camera shutter, the combination, with the pivoted shutters, of the cylinder 3, the follower 19, arranged within said cylinder and provided with a pin, 15, engagingv both of said shutters at a point be* tween their pivots, a spring, 31, connected with said follower, and the adjustable brace 37, adapted to be engaged with said spring, for the purpose specified.

3. The combination, in a photographic-calm IOO IIO

era shutter, ol' a pneumatic cylinder controlling the operating mechanism of said shutter, a bulb connected with said cylinder, and a cut-off valve between said cylinder and said bulb, whereby communication between said bulb and said cylinder maybe ent off and the air confined in said cylinder, for the purpose set forth.

4. The combination, in a photographic-camera shutter, with the movable shutters, of the cylinder 3, the follower lf), arranged therein and connected with said shutters, the dog 2T, arranged to engage said follower', and the piston 22, arranged within said follower and provided with the finger 32, adapted to release the dog 27 as the piston moved within the follower, substantially as described.

5. The combination, in a photographie-carnera shutter, with the pivoted shutters, of the cylinder 3, the air-bulb connected therewith, the follower arranged within said cylinder and connected with said shutters, and the pivoted stop Si, adapted to be arranged in line with said follower, substantially as described.

(E. The combination, in a photographic-camera shutter, with the movable shutters, of the cylinder 3, the air-bulb connected therewith, a follower in said cylinder and connected with said shutters, and a lock holding saidfollower when it is drawn back or forced out in said cylinder.

7. The combin ation, in a pliotographic-cainera shutter, with the pivoted shutters, of the cylinder E3, the air-bulb connected therewith, the follower l0,arranged within said cylinder and connected with both of said shutters, and the pivoted dog 27, adapted to engage said follower and lock it either when it is forced outward in said eylinderor retracted therein, substantially as described.

S. rl`he combination, in a photographic-camera shutter, with the movable shutters, of the cylinder 3, the follower l5), arranged therein and connected with said shutters, the spring 3l, connected with said follower, a locking device engaging said follower and holding it in its retracted position against the tension of the spring, the piston 22, arranged within said follower and adapted to move therein, and provided with a releasing` device engaging the lock which holds said follower, substantially as described.

ln witness whereof we have hereto set our hands this 18th day of May, 1888.

RALPH D. CLEVELAND. CHARLES A. HOFFMAN. In presence of- R. H. SANFORD, A. C, PUL. 

